What am I doing wrong??

Here is a link to an MSDN example that addresses this

http://msdn.microsoft.com/en-us/library/aa979305(v=vs.71).aspx

It creates an array of doubles, calls a VFP COM server to calculate the determinant. It looks to me that I am doing a very analogous thing.



>In other parts of my COM server, I pass parameters by reference. Here is another procedure in the server that works fine both from VFP and C++ clients:
>
>

>PROCEDURE GetDatFilesFromvFBDPatVisits(sFBDDataSource AS String , nPatientNo AS Integer @, nVisitID as Integer @, ;
>		nFileID AS Integer @, sFilename AS String @) 
>

>
>And, I call this by
>

>Result = Thisform.oNPVD.GetDatFilesFromFBDPatVisits("FBD on JIM", @nPatientNo, @nVisitID, @nFileID, @cFilename)	
>

>
>But, none of these are byte arrays.
>
>
>>In VFP you need to call it by reference, e.g.
>>
>>DIMENSION aBlobData[nFileSize] AS Byte
>>thisform.oNPVD.GetvFBDBlob(nFileID, @aBlobData) -- array populated with .F. at present
>>
>>However, I think there may be problems related with COM and passing parameters by reference - I don't recall right now.
>>
>>>>>Naomi,
>>>>>
>>>>>Thanks for your quick response.
>>>>>
>>>>>I have done the things you suggested. Again, it works when I create the object directly for the PRG file. When I build the COM EXE, i no longer get the error that aBlobData is undefined. However, at runtime, I get the error in the FOR loop saying "Invalid subscript reference".
>>>>>
>>>>>Jim
>>>>>
>>>>>
>>>>Can you post code that invokes this function and also the code that checks the array size.
>>>
>>>Here is the code that invokes the function:
>>>

>>>DIMENSION aBlobData[nFileSize] AS Byte
>>>thisform.oNPVD.GetvFBDBlob(nFileID, aBlobData)
>>>

>>>
>>>Here is the code at the beginning of GetvFBDBlob:
>>>

>>>FUNCTION GetFBDBlob(nFileID AS Integer, aBlobData AS Byte ) AS Integer
>>>   EXTERNAL ARRAY aBlobData
>>>   LOCAL nResult AS Integer, nBlobSize AS Integer
>>>   MESSAGEBOX("length of aBlobData: " + STR(ALEN(aBlobData)))
>>>

>>>
>>>When I build the COM, and then run my VFP client, I get an error message saying "ABLOBDATA is not an array"
>>>
>>>I have tried calling with and without '@" in the call: GetvFBD(nFileID, @aBlobData) and GetvFBD(nFileID, aBlobData). Get the same error message.
>>>
>>>
>>>Jim